Judging the Celebrity Reality TV Judges

Britney Spears and Demi Lovato are bound for the "The X Factor." But are they ready?

Spears showed off bloody, bitten fingernails at a Fox press conference announcing her new gig this week.

"The poor thing looked like a complete deer in headlights," said Matt Whitfield, editor of Yahoo TV. "She can't even handle a press conference? How is she going to be able to handle live TV and a huge audience?"

The history of celebrity reality TV judges is rife with casualties. Ellen DeGeneres. Nicole Scherzinger. Paula Abdul -- though her flubs at least made for good television. Given that, why would Spears and Lovato, a veteran pop star and a fledgling one, be interested in risking their reputations?

"Having that venue where you can reach millions of people a week and work in plugs about your own music, you own tour, it's pretty appealing," said Michael Slezak, senior editor and resident reality TV expert at TVLine.com. "Especially if you're a pop star but not of the Barbra Streisand variety ,where you know that people are going to pay large amounts of money to hear you sing in 20 or 30 years. You want to diversify your brand and be more of multi-hyphenate."

Surely, the paycheck sweetens the deal. Spears, 30, is making a reported $15 million for her stint at "The X Factor" judges' table, while Lovato, 19, is rumored to be pulling in $1 million. It could also be a low-stress gig for stars who, not long ago, were under a psychiatric hold (Spears) and in treatment for bulimia and cutting (Lovato).

But that's only if they do well. They can learn from celebrity reality TV judges who've flourished, flailed, and failed:

Michael Becker/AP Photo

Ellen DeGeneres

TVLine's Slezak called DeGeneres' one season stint on "American Idol" "probably the most high-profile failure of a reality show judge."

"You look at someone like Ellen who hosted the Oscars and you think, she won't have a problem giving funny, succinct feedback on live television," he said. "But she was awful. You have to be good on live TV, you have to be able to understand what you're critiquing, you have to be funny, and you have to be willing to be honest."

DeGeneres is reported to have made between $5 and $7 million for judging the ninth season of "Idol." Yahoo's Whitfield pointed out that's the same season the show's ratings began to slide.

"The show kind of jumped the shark at that point," he said. "Every week, she kind of fell into the trap of not wanting to hurt the constant's feelings. The reason why this show blew up was because Simon Cowell was a meanie. She was never willing to go there."

"Idol's" numbers haven't recovered, and they've been revamping the show ever since to keep up with the seemingly endless numbers of reality talent competition shows. Verdict: Failed.

Michael Becker/AP Photo

Paula Abdul

Abdul's performance was a highlight (or not) of "American Idol."

"You can't say she's really 'good' at her job," Slezak said, pointing out that one night during season seven, Abdul critiqued a performance that hadn't yet happened.

"She's not good at reading a script, but in terms of entertainment factor, there's probably been no other reality show judge who's been entertaining just by being loopy and ridiculous," he said. "I think that was her purpose. No one was looking to Paula for amazing singing advice."

Indeed, she had a habit of calling contestants "beautiful" no less than 20 or 30 times an episode. She left "Idol" in 2009 after not getting an $8 million salary increase (she was reportedly making $4 million a year at the time she left). She took another shot at reality TV gavel-banging on the first season of "The X Factor" before the ax came down.

"She should have never been on 'The X Factor,' Whitfield said. "The drama between the judges took away from the talent that was on the show." Verdict: Flailed.

Art Streiber/NBC

Christina Aguilera

Her outfit choices be damned, Aguilera nails it when it comes to judging and fostering hopefuls on "The Voice."

"She's not popular and she's not necessarily likeable," Slezak said, "but in season two of 'The Voice,' she really stepped up her game and did a great job of pinpointing what the acts needed to work on and what their strengths and weaknesses were."

Aguilera has the Grammy awards and record sales to justify her being on the show (they helped her score her estimated $10 million salary). But she gets embroiled in drama that hurts her credibility, like the feud between her and Adam Levine over "Voice" runner-up Tony Lucca.

"I think it's tough for her because she's up there with three other guys," Whitfield said. "She really is kind of the best mentor there, but with live TV, when she gets roped into the drama, she falls apart at the seams." Verdict: Flourished.

Warwick Saint/Fox

Jennifer Lopez

"Let's be honest," Whitfield said, "J-Lo is not known for her singing prowess." Which makes it all the more impressive that Jenny From the Block has come to be known as one of the more credible judges in "American Idol" history. (That may have something to do with whom she's sitting next to -- more on that later.)

While Slezak said Lopez "had some real growing pains" when she started judging "Idol;" for her second season on the show, she came back stronger.

"She'll never be as mean as Simon Cowell or as blunt as Christina Aguilera , but I think she's stepped up her game," he said. "She's getting a solid 'B' at this point."

She's being paid a reported $12 million a year -- a lot of money for a "B." But Slezak believes Fox and the show's producers are happy with her.

"She's probably the MVP of that judging panel," he said. Verdict: Flourished.

Michael Becker/FOX

Steven Tyler

If there's one judge who should be weary of losing their proverbial black robe, it's Steven Tyler. Though he isn't making J-Lo money, he's reportedly banking millions but he may not be worth the cost.

"I love him, the audience loved him, however he really isn't bringing anything new to the show," Whitfield said. "I really think the show would benefit by replacing him. I just don't think that he's doing a great job."

The Aerosmith frontman's poor health caused concern before he signed on to "Idol" in 2010. Now, it appears his hard days of rocking and rolling have affected his cognitive skills.

"I don't know how invested he is in the process," Slezak said. "He seems to wake up every few minutes and blurt something out. Everything is 'beautiful' in his world, he blurts out 'beautiful' 20 or 30 times a show."

And we know how well that worked out for Paula Abdul. Verdict: Failed.